Detailed chain of events - E+ integrated with PythonActor of BCVTB?

edit

I've seen models that have both EnergyPlus modules and apart from that, has a PythonActor module to interface (send and receive data, etc).

The PythonActor starts by receiving data first. ( using self.input.get() [so some data from E+ is passed onto the pythonActor, I presume] )

Can someone please explain, at a very detailed and microscopic level, as to what happens when I click the "Run" button on the model (and henceforth). {basic skeletal model is shown in the picture}